Open Bitcoin Core. Go to Help > Debug Window > Console. In the box at the bottom, type
dumpprivkey 1LWJ1Pxkx8vSJSLCLFYChbrRW7WGnnxuTJ
It should then return a string in black text. That is your private key.
Now open Electrum. Make a new wallet (File > New/Restore). Give it a name. Then choose the option for "Standard wallet" and click Next. Choose "Use public or private keys" and click Next. Copy and paste the private key you got earlier into the box. Then click Next. Follow the rest of the instructions in the wizard and you should be good to go.
I really hate it when people don't read the generic instructions and ask for the specific hand-holding instructions. Can't you read??